A conventional rolling element used in a linear rail such as shown in FIG. 7 generally includes a rails 10 and a sliding element 20 slidable on the rails 10 with rollers (not shown) located between the rails 10 and the sliding element 20. Two end caps 30 are connected to the sliding element 20 and a scrub element 31 is connected to each of the end caps 30. A lubricant inlet 32 extends through the scrub element 31 and is connected to the end cap 30 so as to feed lubricant to the rollers via the inlet 32. The lubricant inlet 32 protrudes from the sliding element 20 in the direction that is the same as the movement of the sliding element 20 so that the effective distance of the sliding element 20 is subtracted by the length “L” of the lubricant inlet 32. Nevertheless, the size of the lubricant inlet 32 has its minimum limitation and it is difficult to align the hole of the inlet 32 with the hole in the sliding element 20. It is also difficult to seal the connection of the lubricant inlet 32.
The present invention intends to provide a lubrication system for a rolling element wherein the lubrication system is integrally connected to the sliding element and occupies a limited space.